Thank you to everyone who sent in their suggestions for what we could call our new puppy. In the end, after much debate (some of it quite heated), my son suggested 'Yoda', after the little Jedi in Star Wars. (The puppy isn't green, of course, but he does have sticking out ears, which may or may not go upright at some point, depending on whatever it is he's actually crossed with).
Wise beyond his years he is.